Contaminant resistant fluid supply system



March 12, 1968 F. PINKAS ETAL 4 CONTAMINANT RESISTANT FLUID SUPPLY SYSTEM Filed March 20, 1967 5 Sheets-Sheet l March 12, 1968v P. F. PINKAS ETAL 3,372,646

CONTAMINANT RESISTANT FLUID SUPPLY SYSTEM Filed March 20, 1967 5 Sheets-Sheet 5 United States Patent Ofiice 3,372,646 CONTAMINANT RESISTANT FLUID SUPPLY SYSTEM Peter F. I inlras, Cleveland, and Chester J. Brian, J12,

Chagrin Falls, Ohio, assignors to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Continuation-impart of application Ser. No. 385,206, July 27, 1964. This application Mar. 20, 1967, Ser. No. 641,080

8 Claims. (Cl. 103-126) ABSTRACT or ran DISCLOSURE A pressure loaded gear pump including a contaminant resistant fluid supply system. The contaminant resistant arrangement includes means for cleaning a portion of the pumped fluid which is in turn utilized to pressure load the pump bearings and cleanse the relatively slidable surfaces of the bearings and pumping gears. Passages are formed in the pump hearings to deliver the fluid to the relatively slidable surfaces, and slots, communicating with the passages are provided in the pumping gear side walls to distribute the cleansing fluid.

Cross reference to related applications This application is a continuation'in-part of United States application for Letter Patent 385,206, filed July 27, 1964, by Peter F. Pinkas and Chester J. Brian, Jr., entitled Contaminant Resistant Fluid Supply System.

Bnckgrozznd of the invention This invention relates to a contaminant resistant fluid supply system and more particularly to a fluid supply system that may be utilized in conjunction with a pressure loaded gear pump.

t is well known that a certain amount of contaminants such as dirt, metal, oxides, and the like are present in a great majority of liquids that are pumped by gear pumps and these contaminants are a particular problem in the pumping of liquid fuel. Prior to this invention, gear pumps and especially pressure loaded gear pumps of the type disclosed in US. Patent 2,420,622 were subject to a great deal of wear on their gear and bearing faces as well as the gear journals due to the aforementioned contaminants becoming lodged therein. These contaminants caused wearing action on the gear and bearing faces as well as the gear journals.

In all gear pumps, it is necessary in order to maintain efficiency of the pump, to provide a seal between the radially extending surfaces of the bearing bushings and the adjacent side faces of the gears. In pressure loaded gear pumps, this seal is maintained by diverting a portion of the liquid from the outlet of the pump to an area behind the axially slidable bearing bushings. This is done in order to maintain sufiicient pressure on the axially slidable hearings to cause them to exert pressure against the gear faces to seal that area between the gear faces and the axially slidable bearings as Well as the static body bearings. By static body bearings, it is meant those bearings distinguished from the axially slidable bearings that remain fixed with respect to the pump housing. That portion of the liquid which is diverted to pressure load the axially slidable bearings also contains contaminants. Due to the closeness of the seal between the bearing bushing faces and the gear faces during pumping, the tendency of the bearing faces to wear is a problem which is intensified due to the aforementioned abrasive contaminants.

Patented Mar. 12, 1968 Summary of the invention Briefly described, the present invention substantially eliminates wear on the gear and bearing faces as well as the gear journals in a pressure loaded gear pump caused by contaminants in the liquid being pumped. This is accomplished by diverting a portion of the discharge fioW of the gear pump through a cleaning filter to a booster pump whereby a slight pressure increase is imparted to the liquid prior to its entrance into the pump to pressure load the axially slidable bearing bushings of the gear pump.

The diverted liquid is utilized to pressure load the pump, i.e., move the axially slidable pressure loadable bearings toward the faces of the gears, and in addition, provides a cleaning action around the periphery of the axially slidable bearings which eliminates the possibility of their seizing in the body bore. A portion of the liquid that has been diverted and filtered is also allowed to pass through the pressure loadable axially movable bearings to pass between the gear faces and bearing faces to thus cleanse the surface during operation of the pump. The filtered liquid being free of contaminants, substantially prevents the normal wear of the gear and bearing faces as well as the gear journals and substantially increases the eificient operating life of the pump.

The aforementioned filter utilized in this invention may be of any type adapted to be placed in the discharge line of the gear pump, however, a wash flow filter wherein the filter is self-cleansing is preferred. The specific booster pump that is utilized to increase the pressure of the liquid passing into the gear pump is relatively unimportant and may be another gear pump, centrifugal pump, vane pump, or the like.

The invention will become apparent to those skilled in the art upon consideration of the following written description, appended claims, and attached drawings of embodiments of this invention, wherein:

Description of drawings FIGURE 1 is a schematic view of a contaminant resistant fuel supply system utilizing the present invention;

FIGURE 2 is an axial cross-sectional view of a gear pump which may be incorporated in the invention;

FIGURE 3 is a cross-sectional view taken on line 3-3 of FIGURE 2 showing the two adjacent complementary end bearing bushings;

FIGURE 4 is a cross-sectional view taken on line 4-4 of FIGURE 2 showing the adjacent complementary end bearing bushings; and

FIGURE 5 is a perspective view of the gear teeth showing relief grooves in the faces thereof.

FIGURES 6 and 7 are fragmentary views showing a slightly modified form of the invention.

FIGURE 8 is a perspective view of a gear of the modification of FIGURES 6 and 7 showing relief grooves in the gear face.

Detailed description Referring now more particularly to the drawings, FIGURE 1 is a schematic view showing the inlet line 10 to a gear pump 12 as well as the outlet line 14. The outlet 14, i.e., the high pressure side of the pump is directed through a filter 18. In a preferred embodiment of this invention, the filter 18 is a wash flow filter. By wash flow filter it is meant a filter that is self-cleansing. A portion of the outlet flow is diverted at the filter 18, via line 20, to a booster pump 22 where the pressure is slightly increased above that of the outlet pressure in line 14. The flow from booster pump 22 passes through line 24 into gear pump 12 via ports 26, 28, 30, and 32 shown in FIGURE 2.

FIGURE 2 is a cross-sectional view of a pressure loaded gear pump that operates under a pressure loading principle. That is, a portion of the discharge flow is diverted behind axially slidable bearings for the provision of a pumping seal between the gear side faces and the bearing bushings.

The gear pump of FIGURE 2 is comprised of a housing 34 which contains parallel intersecting cylindrical chambers 36 and 38 which receive gears 40 and 42 which mesh in the intersecting area. There is a housing end wall closure plate 44 attached to the open end of housing 34 by bolts or the like (not shown). The inner exposed surface of closure 44 forms end Walls 46 and 48 of gear chambers 36 and 38 respectively. The end walls 46 and 48 extend radially parallel to the opposite end walls 50 and 52 of gear chambers 36 and 38. The gears 40 and 42 have a coaxial thickness less than the coaxial thickness of chambers 36 and 38 which provides annular spaces on at least one side of the gears.

Gear chamber end walls 46, 48, 59, and 52 are formed with reduced bore extensions 54 and 56, within end wall closure plate 44 and bore extensions 58 and 60 within body 34 respectively. The gears 46 and 42 are provided with oppositely extending coaxial journals 62, 64, 66, and 68. These journals are received coaxially in the aforementioned bores.

The bearing bushings 7%, 72, 74, and 76, hereinafter described, are of particular importance to the operation of the contaminant resistant fluid supply system of the present invention. These bearings are interposed between the housing and the gear journals and are comprised of two axially movable pressure loadable bearings and 72 and two static body bearings 74 and 76. By static, it is meant that these bushings are fixed with respect to the housing and are not designed to move axially as are the axially movable bearings. The static bearings 74 and 76 are comprised of tubular portions 78 and 80 which extend around the gear journals within the bores 58 and 60 respectively. These bearings, i.e., 74 and 76 terminate in radially outwardly extending flanges 82 and 84 respectively, which portions abut the adjacent gear faces 98 and gear chamber end walls 50 and 52 respectively. The floating bearings 70 and 72 are also comprised of tubular portions 81 and 83 respectively which extend into closure plate 44 as well as around their respective journals within bores 54 and 56 respectively. These bearings, i.e., 70 and 72 also terminate in flange portions 86 and 88 respectively which portions shut the adjacent gear faces 96 and gear chamber end walls 46 and 48 respectively. There are sealing rings 90 on the tubular portions 78 and 80 of the static body bearings as well as sealing rings 91 on the tubular portions 81 and 83 situated within closure plate 44 of the axially movable pressure loadable bearings 70 and 72. The sealing rings 90 and 91 are designed to prevent the passage of fluid between the tubular portions of the bearings and the surrounding housing.

The terminal flanges 86 and 88 of the axially movable bearings move toward the gears 40 and 42 when fluid enters the gear pump under pressure through ports 26 and 28 to chambers 92 and 94 within bearings 70 and 72 respectively. The pressure is slightly increased over that of the output pressure from the gear pump as a result of the action of booster pump 22. As fluid enters the gear pump and pressure loading chambers 92 and 94 on axially movable bearings 7 0 and 72, suflicient pressure is exerted to place the bearings in contact with the gears. It will be noted that chambers 92 and 94 contain loading springs 93 which provide the requisite pressure to place the bearing faces 96 in contact with the gear faces 98 at the time that the pump is started.

As the pump is actuated, fluid is passed out of the pump via outlet line 14 which is the high pressure line. The fluid passes into filter 18 where a portion is cleaned and diverted via passage line 20 to booster pump 22. Booster pump 22 imparts a slight pressure increase, over that of outlet pressure, to the diverted fluid and passes it via passage line 24 into pump ports 26, 28, 3t and 32 of the gear pump shown in FIGURE 2. That fluid which has been cleaned and placed under greater pressure than that of the outlet of the pump passes from ports 26, 28, 30 and 32 in the housing of the pump into the axially movable bearing pressure loading chambers 92 and 94 as well as passages 100 which extend through the static body bearings as well as the axially movable bearings. Thus, the fluid is carried to the bearing faces 8'6 and gear faces 98.

As shown in FIGURES 3 and 4, there is an arcuate groove 192 in each of the bearing faces which is in communication with passages 100. Arcuate grooves 182 are machined so as to be situated below the gear root diameter.

The diverted fluid is dispersed radially outwardly from grooves 182. As the fluid is forced radially outwardly from grooves 102, it is directed into radial slots 164 situated on the faces of the gear teeth as well as downwardly into the journals. Slots 194 insure the complete distribution of the filtered fluid over the gear faces. In this manner, the filtered fluid serves to keep the gear and bearing faces free of contaminants as well as provide clean fluid within the journals to thereby prevent the entrance of contaminants to the journals.

As shown, the arcuate grooves 182 do not extend completely around the bearing face but are located adjacent that area exposed to discharge pressure.

It will be noted that contaminants are prevented from entrance into the gear and bearing faces as well as journals due to the increased pressure on the diverted fluid. There are relief grooves 106 in the journals and relief grooves 118 in the bearings which serve as lubrication grooves for the journals and bearings respectively. The relief grooves in the bearings relieves fluid along the journals to inlet in a manner well known in the art. The arcuate configuration of grooves 102 is utilized primarily because the inlet side or high pressure side creates the greater contaminant problem. However, a complete circumferential groove fed by periodically spaced passages 100 would be equally appropriate to provide pressurized fluid for the cleaning of the bearing and gear faces.

FIGURE 5 shows the gear faces with radially extending slots 104 placed therein. It will be noted that the configuration of slots 104 may be altered to provide distribution of fluid over the gear and bearing faces, the specific configuration is provided in an illustrative rather than exclusive sense.

Turning now to the embodiment of FIGURES 6, 7, and 8 there is shown an arrangement similar to the arrangement of FIGURES 1 to 5 except as hereinafter described. It may therefore be assumed that the embodiment includes elements such as those described with respect to the embodiment of FIGURES l to 5 unless otherwise stated.

In the arrangement shown in FIGURES 6, 7, and 8 bearing bushings 270, 272, 274, and 276 are provided which support pumping gears such as the gear 227 of FIGURE 8. The bearings include gear contacting surfaces 296 and the bearings are pressure loaded in the manner described with respect to the embodiment of FIGURES 1 through 5. The contacting surfaces 296 cooperate with the gear side faces 298 to provide the required pumping sealing relation.

Longitudinal passages 200 are provided in the hearing bushings which extend through the bearings and define openings at the surfaces 296. The cleansed fluid therefore may pass through these passages to the relatively sliding surfaces 296 and 298.

The gears 297 include generally radially directed grooves or slots 284 in the side faces 298. These grooves extend radially inwardly a distance to allow fluid communication between the grooves and the passages 200 of the bearings upon rotation of the pumping gears.

Thus, clean fluid may pass through the passages 200 and into the slots 204 for distribution along the surfaces 296 and 298 of the bearing bushings and gears. In this manner the surfaces are cleansed of contaminants to prevent excessive wear and an effective pumping seal between these surfaces is readily maintained.

While this invention has been described in conjunction with :a specific type gear pump, it will be understood by those skilled in the art that this is by way of illustration and not by way of limitation; and the scope of this invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit.

We claim:

1. A pressure generating pump including a contaminant resistant fluid supply system comprising: a housing including a pump inlet and a pump outlet, a pair of intermeshing gears disposed in said housing adapted to pressurize a fluid to be pumped, each of said gears including a pair of radially directed side faces, bearing members supporting said gears in said housing, said bearing members including inner faces adapted to be placed in radially directed contact with said side faces of said gears, and longitudinal passages extending therethrough defining openings at said inner faces, at least one of said bearing members supporting each said gear being axially movable in a direction toward said gear to effect a pumping seal relation between said support bearing inner faces and said gear side faces, said axially movable bearings including outer terminal surfaces defining with said housing a pressure loading chamber, a fluid filter adapted to clean a portion of said fluid pumped by said pressure generating pump, passage means communicating with said filter including a fluid inlet, a cleaned fluid outlet and an outlet for unfiltered fluid, and means adapted to divert a portion of said pumped fluid to said cleaned fluid outlet, a conduit communicating between said pump outlet and said filter inlet, a booster pump including an inlet, and a discharge, said booster being adapted to receive cleaned fluid and to increase the pressure thereof to a pressure greater than the outlet pressure of said pressure generating pump, a conduit communicating between said cleaned fluid outlet of said filter and said booster pump inlet, and means communicating between said booster pump discharge and said pressure loading chambers of said pump and said longitudinal passages of said bearings.

2. A pressure generating pump including a contaminant resistant fluid supply system as claimed in claim 1 where in said filter is a wash flow filter.

3. A pressure generating pump including a contaminant resistant fluid supply system as claimed in claim 2 wherein said inner faces of said bearing members include arcuate grooves, said openings defined by said longitudinal passages at said inner faces being disposed within said grooves and providing communication between longitudinal passages and said grooves, said grooves being below the root diameter of said gears.

4. A pressure generating pump including a contaminant resistant fluid supply system as claimed in claim 3 wherein said arcuate grooves of said bearings exend only partially around said bearing faces with said grooves being adjacent said pressure generating pump.

5. A pressure generating pump including a contaminant resistant fluid supply system as claimed in claim 1 wherein said gear side faces include generally radially directed grooves adapted to communicate with said longitudinal passages of said bearings upon rotation of said gears.

6. A contaminant resistant fluid supply system for a pump comprising a pressure generating pump including a. housing including a pump inlet and a pump outlet, a pair of inter-meshing gears disposed in said housing adapted to pressurize a fluid to be pumped, each of said gears including a pair of radially directed side faces, bearing members supporting said gears in said housing, said bearing members including longitudinal passages extending therethrough, and inner faces adapted to be placed in radially directed contact with said side faces of said gears, at least one of said bearing members sup porting each said gear being axially movable in a direction toward said gear to effect a pumping seal relation between said support bearing inner faces and said gear side faces, said axially movable bearings including outer terminal surfaces defining with said housing a pressure loading chamber a fluid filter adapted to clean a portion of said fluid pumped by said pressure generating pump, said filter including a fluid inlet, a cleaned fluid outlet and an outlet for unfiltered fluid, and means adapted to divert a portion of said pumped fluid to said cleaned fluid outlet, a conduit communicating between said pump outlet and said filter inlet, a booster pump including an inlet, and a discharge, said booster being adapted to receive cleaned fluid and to increase the pressure thereof to a pressure greater than the outlet pressure of said pressure generating pump, a conduit communicating between said cleaned fluid outlet of said filter and said booster pump inlet, and means communicating between said booster pump discharge and said pressure loading chambers of said pump and said longitudinal passages of said bearings.

7. A contaminant resistant fluid supply system for a pump as claimed in claim 6 wherein said filter is a wash flow filter.

8. A contaminant resistant fluid supply system for a pump as claimed in claim 7 wherein said gear side faces include generally radially directed grooves adapted to communicate with said longitudinal passages of said bearings upon rotation of said gears.

References Cited UNITED STATES PATENTS 2,500,719 3/1950 Ungar 103-126 2,845,868 8/1958 Norlin 103-11 2,887,058 5/1959 Aspelin et a1. 103-4 2,963,980 12/1960 White 103-87 3,003,425 10/1961 Flowers 103-126 DONLEY J. STOCKING, Primary Examiner. WILLIAM L. FREEH, Examiner. 

